This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A090148 #5 Mar 30 2012 17:30:56
%S A090148 19,29,59,79,89,229,449,11119,22229,44449,111119,444449,11111119,
%T A090148 55555559,555555555559,22222222222229,88888888888889,
%U A090148 11111111111111119,88888888888888889,555555555555555559,55555555555555555555555559
%N A090148 Primes of the form identical digits followed by a 9.
%H A090148 Vincenzo Librandi, <a href="/A090148/b090148.txt">Table of n, a(n) for n = 1..40</a>
%t A090148 Select[ FromDigits /@ Flatten[ Table[ PadLeft[{9}, i, # ] & /@ {1, 2, 3, 4, 5, 6, 7, 8, 9}, {i, 2, 16}], 1], PrimeQ[ # ] &]
%K A090148 nonn,base
%O A090148 1,1
%A A090148 _Robert G. Wilson v_, Nov 22 2003